msm8916: Add the long press power on feature support

Add shutdown detection in target init.  We will choose shuting
down device when the power key is pressed not long enough.
This feature is disabled by default, and OEMs could set
LONG_PRESS_POWER_ON to enable it.

Change-Id: I9d73a76265da48e0d3d79f9be2400a596664343f
1 file changed